The Longevity Vault

The Longevity Vault

Is Your Melatonin Actually Helping Your Sleep?

The chronobiology of melatonin & why it hasn't delivered consistent results you hoped for

Kat Fu, M.S., M.S.'s avatar
Kat Fu, M.S., M.S.
Mar 09, 2026
∙ Paid

“I’ve been taking melatonin for two years and I don’t know if it’s doing anything.”

I hear this more than anything else. Someone started because sleep felt off — maybe a friend suggested it was a natural, reasonable option — and now, months or years later, they’re still taking it, still uncertain, and not sure how to think through it.

When a person’s body expects melatonin — is highly individual. The situations where it makes a difference are also narrower than many expect.

If you have been taking melatonin for months and years and you are still struggling with sleep, I explain why that might not be the right tool for your sleep issues, how it might be instead making your sleep worse & what you can do about it.

—Kat

P.S. If you missed last week’s video, I covered 3 underappreciated reasons you may still be waking at 3 a.m. even after moving your caffeine cutoff earlier, cooling down your room, and cutting screens. You can watch it here


References

  • Kennaway DJ. The dim light melatonin onset across ages, methodologies, and sex and its relationship with morningness/eveningness. Sleep. 2023 May 10;46(5):zsad033.

  • Cagnacci A, Soldani R, Yen SS. Hypothermic effect of melatonin and nocturnal core body temperature decline are reduced in aged women. J Appl Physiol (1985). 1995 Jan;78(1):314-7.

  • Sateia MJ, Buysse DJ, Krystal AD, Neubauer DN, Heald JL. Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults: An American Academy of Sleep Medicine Clinical Practice Guideline. J Clin Sleep Med. 2017 Feb 15;13(2):307-349. d

  • Arendt J, Aulinas A. Physiology of the Pineal Gland and Melatonin. [Updated 2022 Oct 30]. In: Feingold KR, Adler RA, Ahmed SF, et al., editors. Endotext [Internet]. South Dartmouth (MA)

  • Hamel C, Horton J; Authors. Melatonin for the Treatment of Insomnia: A 2022 Update: Rapid Review [Internet]. Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2022 May.

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